I 
167 
Scientific Intelligence . — Optics . 
have been regularly observed by astronomers. It was first seen 
in 1786 ; afterwards in 1795, 1805, 1819, and 1822, and in the 
present year. It makes a complete revolution in about 1207 
days, or 3J- years. 
acoustics. 
2. A Table shewing the Results of Experiments on the Ve~ 
locity of Sound, as observed by different Philosophers *. 
Time 
Country 
Length of 
Velocity of Sound 
Names of Observers. 
when 
where 
Basis in 
per Second in 
made. 
made. 
Feet. 
Feet. 
Mersenne, 1 
France, 
1469.88 
Florentine Philosophers, 2 
1660 
Italy, 
5905.8 
1184.44 
Walker, 3 
1698 
England, 
2624.8 
1305.83 
Cassini, Huygens, &c. 4 
France, 
6906.50 
1151.63 
Flamstead and Halley, 5 
England, 
16405.0 
1141.78 
Derham, 6 
1704 1 
1705 / 
England, | 
5249.6 
to 6562. 
¥— ‘ 
CO 
French Academicians, 7 
1738 
France, j 
75177.55 
& 93593.8 
1092.57 at 32° 
F. 
Blaneoni, 8 
1740 
Italy, 
7874.0 
1043.35 
La Condamine, 9 
1740 
Quito, 
67401.58 
1112.25 
La Condamine, 1 0 « 
1744 
Cayenne, 
129366.54 
1174.59 
T. F. Mayer, 1 1 
1778 
Germany, 
3702.40 
1105.69 
G. E. Muller, 1 2 
1791 
Germany, 
8530.6 
1108.97 
Epinoza and Banza, 1 3 
1794 
Chili, 
53627-94 
1168.50 
Benzenberg, 1 4 
1809 
Germany, 
29765.23 
1092.57 at 32° 
Arago, Mathien Prony, 1 5 
1822 
France, 
61065.97 
1086.0 
Moll, Van Beek, and > 
Kuy tenbrower, 1 6 j 
1823 
Netherlands, 
5797290.7 6 
J 1089-7445 at 
{ 32° F. dry air. 
1 Mersenne de Arte Ballistica, prop. 39. 
2 Tentamina Experim. Acad. del. Cimento, L. B. 1738, part ii. p. 116. 
3 Phil. Trans. 1698, No. 247* 
4 Duhamel, Hist. Acad. Reg. 1. ii. sect. 3. cap. ii. 
5 Phil. Trans, 1708 and 1709. 
fi Id, ibid. 
7 Mem. de I’Academie des Sciences, 1738 and 1739. 
8 Comment. Bononienses, vol. ii. p. 365. 
3 La Condamine, Introduction Historique, &c. 1751, p. 98. 
10 Mem. de 1’Acad. Royale des Sciences, 1745, p. 488. 
11 J. T. Mayer, Praktische Geometrie, Gottingen, 1792, b. i. p. 166. 
1 2 Muller, Gotting. Gelehrt. Anzeige, 1791, st. 159, et Voigts Magazin, 
&c. b. 8. st. i. p. 170. 
1 3 Annales de Chimie et de Phys. t. vii. p. 93. 
1 4 Gilbert’s Annalen, neue Folge, b. v. p. 383. 
1 5 Connoissance des Terns, 1825, p. 361. 
* From Von Moll’s Memoir on the Velocity of Sound in Phil. Trans . for 
1824, part ii. 
